1. Field of the Invention
This invention relates to a system for inspecting an image on a sheet such as a printing film and more particularly detecting a difference between an image on an original or primary printing film and an image on a corrected or secondary printing film to determine the omission of necessary image information from the secondary printing film and the addition of unnecessary information, such as that represented by dirt, to the secondary printing film.
2. Prior Art
In the production of printing films or the like, it is necessary to detect any defect contained on the secondary printing film produced based on the primary printing film. Such detection has heretofore been carried out by displaying the image of the secondary film on a display screen and checking the film image displayed on the screen with the eye.
In the inspection of the secondary film, it is necessary to check not only the corrected portions of the image which have been made but also any possible defect such as the omission of a character or the like. Therefore, attention is drawn to such corrected portions, so that any error in those portions may be easily found, but it is quite possible that the operator may overlook some defects on the remainder of the image such as the omission of a character.